The overall objective of this research is to improve our understanding of the membrane mechanisms which modulate cell-to-cell communication in mature, developing and cancerous cells. Studies will be carried out on rat liver in an attempt to correlate changes in rapidly frozen and freeze-fractured gap junctions with changes in the intercellular electrical resistivity. Other studies will test the effects of divalent and trivalent cations on the structure of isolated lens junctions and will attempt to define the structure and composition of isolated junctions in control conditions and after exposure to uncoupling agents. Various methodologies including thin sectioning, freeze-fracture, rapid freezing, membrane fractioning, SDS PAGE, intracellular recordings etc. will be applied.